Zune Sync Error

[silent54]

My Zune works fine except for on thing. I'm not should if it's a hardware or software problem but if I add a song to a playlist it generally takes multiple syncs to get the song added to the playlist. This happens all the time and lately it takes long to get it to sync correctly. Sometimes during the sync process, songs would actually be removed but I've been able to add them again going through the multiple sync processes. The sync process will actually tell me that "new song" have been added to device but when I go and look, it hasn't. I believe I have the latest firmware version (3.30) and the latest Zune software.